The study, conducted in Spain in 2011 and 2012 was just published in the Journal of Pediatrics. Researchers performed fitness tests on 2,038 children and teenagers. They then compared the kids’ grades to their fitness, body mass index, body fat, waist circumference, socioeconomic status and parents’ education.

It’s not unusual to find out that exercise and improved brain function go hand-in-hand, but the new finding in this study was that motor ability was most strongly linked to better grades, with aerobic capacity coming in second. Muscle strength on its own wasn’t associated with school performance. Researchers also found that fitness mattered more than fatness.

The study's authors need to conduct more tests to prove cause and effect, but what this could mean is that sports like soccer and basketball that require both cardiovascular fitness and coordination should be promoted more at school to help improve learning for kids.

“Physical activity at the school should be oriented to improve cardiovascular fitness and motor performance to improve academic performance,” said Irene Esteban-Cornejo, a graduate student at the Autonomous University of Madrid who led the study. “You can’t improve one without the other.”